1. Field of the Invention
The present invention relates to an image forming apparatus with a fixing device that is capable of easily removing paper jammed in a nip.
2. Description of the Related Art
A fixing device incorporated in an image forming apparatus is composed of a heating roller and a pressure roller that is in pressure contact with the heating roller. The pressure roller is provided with a pressurizing mechanism to pressure contact the pressure roller to the heating roller. This pressurizing mechanism also serves as a pressure releasing mechanism to release pressure.
However, when a sheet of paper is jammed in the bellows shape in the nip position between the heating roller and the pressure roller, it is difficult for a user to release the jamming of paper. Therefore, a serviceman removes a fixing device from the main body of the image forming apparatus and removes a cover fixed to the fixing device with screws for a user. Further, a serviceman released the pressure roller from the heating roller and removed jammed paper.
A fixing device capable of easily removing jammed paper is disclosed in Japanese Patent Publication No. 2001-318555 (Laid open to public inspection on Nov. 16, 2001). This fixing device is composed of a heating roller, a pressure roller to pressure contact this heating roller, a pressurizing means to pressing the pressure roller to the heating roller, and a pressure releasing lever to release the pressing force of the pressurizing means. Further, this fixing device is provided with a separating mechanism to separate the pressure roller from the heating roller interlocking with the pressing force releasing operation by the pressure releasing lever. That is, the fixing device has the separating mechanism to separate the pressure roller from the heating roller interlocking with the pressing force releasing operation by the pressure releasing lever, a sheet of paper jammed in the bellows shape can be easily pulled out. Accordingly, a jammed paper can be removed certainly without leaving broken pieces of the paper between the heating roller and the pressure roller.
However, the above-mentioned fixing device was fixed with screws or an engaging mechanism in the main body of an image forming apparatus. In this case, when the paper jamming is caused, the fixing device cannot be easily taken out of the main body and there was such a defect that the operability became bad.
In Japanese Patent Publication No. 10-301432 (laid open to public inspection on Nov. 13, 1998), an image forming apparatus capable of releasing pressure of the pressure roller and easily detaching a fixing device from the main body of the apparatus is disclosed. That is, this apparatus is provided with slide rails that are supported slidably in the main body, a fixing device that is held detachably to/from the slide rails, and an operating means provided between the main body and the fixing device for approving the pull-out of the fixing device and releasing the pressure contact between the hearing roller and the pressure roller. According to this structure, when troubles such as paper jamming and the like are caused, the fixing device can be easily removed or installed. In addition, the image forming apparatus is equipped with the pressure contact of the pressure roller releasing mechanism and an effect to easily remove jammed paper is provided. However, the above-mentioned fixing device can be removed easily from the main body of the apparatus but the fixing device is also completely removed from the slide rails. It will be dangerous to remove jammed sheets by putting the heated fixing device on a table. In addition, to insert the once removed fixing device to insert into the main body of the apparatus, the fixing device must be engaged with the slid rails again and a difficult work is required to return the fixing device into the main body of the apparatus. Furthermore, the fixing device is moved along the longitudinal direction of the heating roller and the pressure roller and therefore, the moving distance is long and the work is worrisome.